Abstract
The antimalarial drug artesunate is a semisynthetic derivative of artemisinin, the principal active component of a medicinal plant Artemisia annua. It is hypothesized to attenuate allergic asthma via inhibition of multiple signaling pathways. We used a comprehensive approach to elucidate the mechanism of action of artesunate by designing a novel biotinylated dihydroartemisinin (BDHA) to identify cellular protein targets of this anti-inflammatory drug. By adopting an untargeted proteomics approach, we demonstrated that artesunate may exert its protective anti-inflammatory effects via direct interaction with multiple proteins, most importantly with a number of mitochondrial enzymes related to glucose and energy metabolism, along with mRNA and gene expression, ribosomal regulation, stress responses, and structural proteins. In addition, the modulatory effects of artesunate on various cellular transcription factors were investigated using a transcription factor array, which revealed that artesunate can simultaneously modulate multiple nuclear transcription factors related to several major pro- and anti-inflammatory signaling cascades in human bronchial epithelial cells. Artesunate significantly enhanced nuclear levels of nuclear factor erythroid-2-related factor 2 (Nrf2), a key promoter of antioxidant mechanisms, which is inhibited by the Kelch-like ECH-associated protein 1 (Keap1). Our results demonstrate that, like other electrophilic Nrf2 regulators, artesunate activates this system via direct molecular interaction/modification of Keap1, freeing Nrf2 for transcriptional activity. Altogether, the molecular interactions and modulation of nuclear transcription factors provide invaluable insights into the broad pharmacological actions of artesunate in inflammatory lung diseases and related inflammatory disorders.